Project description:The second leading cause of cancer death for women in the U.S. is breast cancer. Moreover, a significant number of patients with breast tumors acquire resistance to drugs during therapy. To develop targeted therapeutic strategies to combat drug resistance it is essential to understand the basic molecular mechanisms through which cancer cells control sensitivity to chemotherapeutics. To identify new candidate genes and facilitate the discovery of novel drug resistance pathways, we have generated a resistance profile or ?resistome? of etoposide resistant MCF7 breast cancer cells. Differential expression of over 5000 genes (fold change > 2, P value < 0.05) indicate that several drug resistance mechanisms may be operating in these cells, including up-regulation of ABC transporter genes, down-regulation of the drug target and down-regulation of apoptotic genes. Several transcription factors such as RUNX2, SOX9, ETS1 and SMAD3 were up-regulated in the drug resistant cells. Targeted RUNX2 knockdown in the resistant cells using siRNA increased sensitivity to etoposide and also upregulated expression of pro-apoptotic genes indicating that RUNX2 could be a molecular target against etoposide resistance. Differential miRNA (microRNA) expression was observed among the drug resistant and sensitive cells suggesting that miRNA may also play a role in regulation of drug resistance. Hsa-miR-218, which targets ABCC6, was down-regulated in the drug resistant cell line. Transfection of a miR-218 mimic could down-regulate the expression of the efflux pump ABCC6 by 65% in drug resistant cells suggesting that regulation of miRNA may play an important role in etoposide resistance. long summary Refer to individual Series. This SuperSeries is composed of the following subset Series: GSE28413: Expression profile of etoposide-resistant MCF7 (MCF7VP) cells GSE28414: Expression profile of etoposide-resistant MCF7 (MCF7VP) cells with targeted RUNX2 knockdown
Project description:The second leading cause of cancer death for women in the U.S. is breast cancer. Moreover, a significant number of patients with breast tumors acquire resistance to drugs during therapy. To develop targeted therapeutic strategies to combat drug resistance it is essential to understand the basic molecular mechanisms through which cancer cells control sensitivity to chemotherapeutics. To identify new candidate genes and facilitate the discovery of novel drug resistance pathways, we have generated a resistance profile or âresistomeâ of etoposide resistant MCF7 breast cancer cells. Differential expression of over 5000 genes (fold change > 2, P value < 0.05) indicate that several drug resistance mechanisms may be operating in these cells, including up-regulation of ABC transporter genes, down-regulation of the drug target and down-regulation of apoptotic genes. Several transcription factors such as RUNX2, SOX9, ETS1 and SMAD3 were up-regulated in the drug resistant cells. Targeted RUNX2 knockdown in the resistant cells using siRNA increased sensitivity to etoposide and also upregulated expression of pro-apoptotic genes indicating that RUNX2 could be a molecular target against etoposide resistance. Differential miRNA (microRNA) expression was observed among the drug resistant and sensitive cells suggesting that miRNA may also play a role in regulation of drug resistance. Hsa-miR-218, which targets ABCC6, was down-regulated in the drug resistant cell line. Transfection of a miR-218 mimic could down-regulate the expression of the efflux pump ABCC6 by 65% in drug resistant cells suggesting that regulation of miRNA may play an important role in etoposide resistance. RNA from MCF7 and etoposide-resistant MCF7 (MCF7VP) cell lines were hybridized to Affymetrix microarrays. Both samples were run in triplicate
Project description:The second leading cause of cancer death for women in the U.S. is breast cancer, moreover, a significant number of patients with breast tumors acquire resistance to drugs during therapy. To develop targeted therapeutic strategies to combat drug resistance it is essential to understand the basic molecular mechanisms through which cancer cells control sensitivity to chemotherapeutics. To identify new candidate genes and facilitate the discovery of novel drug resistance pathways, we have generated a resistance profile or M-bM-^@M-^XresistomeM-bM-^@M-^Y of etoposide resitant MCF7 breast cancer cells. Differential expression of over 5000 genes (fold change > 2, P value < 0.05) indicate that several drug resistance mechanisms may be operating in these cells, including up-regulation of ABC transporter genes, down-regulation of the drug target and down-regulation of apoptotic genes. Several transcription factors such as RUNX2, SOX9, ETS1 and SMAD3 were up-regulated in the drug resistant cells. Targeted RUNX2 knockdown in the resistant cells using siRNA increased sensitivity to etoposide and also upregulated expression of pro-apoptotic genes indicating that RUNX2 could be a molecular target against etoposide resistance. Differential miRNA (microRNA) expression was observed among the drug resistant and sensitive cells suggesting that miRNA may also play a role in regulation of drug resistance. Hsa-miR-218, which targets ABCC6, was down-regulated in the drug resistant cell line. Transfection of a miR-218 mimic could down-regulate the expression of the efflux pump ABCC6 by 65% in drug resistant cells suggesting that regulation of miRNA may play an important role in etoposide resistance. RNA from etoposide-resistant MCF7 (MCF7VP) cell lines were hybridized to Affymetrix microarrays.
Project description:The second leading cause of cancer death for women in the U.S. is breast cancer. Moreover, a significant number of patients with breast tumors acquire resistance to drugs during therapy. To develop targeted therapeutic strategies to combat drug resistance it is essential to understand the basic molecular mechanisms through which cancer cells control sensitivity to chemotherapeutics. To identify new candidate genes and facilitate the discovery of novel drug resistance pathways, we have generated a resistance profile or ‘resistome’ of etoposide resistant MCF7 breast cancer cells. Differential expression of over 5000 genes (fold change > 2, P value < 0.05) indicate that several drug resistance mechanisms may be operating in these cells, including up-regulation of ABC transporter genes, down-regulation of the drug target and down-regulation of apoptotic genes. Several transcription factors such as RUNX2, SOX9, ETS1 and SMAD3 were up-regulated in the drug resistant cells. Targeted RUNX2 knockdown in the resistant cells using siRNA increased sensitivity to etoposide and also upregulated expression of pro-apoptotic genes indicating that RUNX2 could be a molecular target against etoposide resistance. Differential miRNA (microRNA) expression was observed among the drug resistant and sensitive cells suggesting that miRNA may also play a role in regulation of drug resistance. Hsa-miR-218, which targets ABCC6, was down-regulated in the drug resistant cell line. Transfection of a miR-218 mimic could down-regulate the expression of the efflux pump ABCC6 by 65% in drug resistant cells suggesting that regulation of miRNA may play an important role in etoposide resistance.
Project description:The second leading cause of cancer death for women in the U.S. is breast cancer. Moreover, a significant number of patients with breast tumors acquire resistance to drugs during therapy. To develop targeted therapeutic strategies to combat drug resistance it is essential to understand the basic molecular mechanisms through which cancer cells control sensitivity to chemotherapeutics. To identify new candidate genes and facilitate the discovery of novel drug resistance pathways, we have generated a resistance profile or ?resistome? of etoposide resistant MCF7 breast cancer cells. Differential expression of over 5000 genes (fold change > 2, P value < 0.05) indicate that several drug resistance mechanisms may be operating in these cells, including up-regulation of ABC transporter genes, down-regulation of the drug target and down-regulation of apoptotic genes. Several transcription factors such as RUNX2, SOX9, ETS1 and SMAD3 were up-regulated in the drug resistant cells. Targeted RUNX2 knockdown in the resistant cells using siRNA increased sensitivity to etoposide and also upregulated expression of pro-apoptotic genes indicating that RUNX2 could be a molecular target against etoposide resistance. Differential miRNA (microRNA) expression was observed among the drug resistant and sensitive cells suggesting that miRNA may also play a role in regulation of drug resistance. Hsa-miR-218, which targets ABCC6, was down-regulated in the drug resistant cell line. Transfection of a miR-218 mimic could down-regulate the expression of the efflux pump ABCC6 by 65% in drug resistant cells suggesting that regulation of miRNA may play an important role in etoposide resistance. This SuperSeries is composed of the SubSeries listed below.
Project description:The second leading cause of cancer death for women in the U.S. is breast cancer, moreover, a significant number of patients with breast tumors acquire resistance to drugs during therapy. To develop targeted therapeutic strategies to combat drug resistance it is essential to understand the basic molecular mechanisms through which cancer cells control sensitivity to chemotherapeutics. To identify new candidate genes and facilitate the discovery of novel drug resistance pathways, we have generated a resistance profile or ‘resistome’ of etoposide resitant MCF7 breast cancer cells. Differential expression of over 5000 genes (fold change > 2, P value < 0.05) indicate that several drug resistance mechanisms may be operating in these cells, including up-regulation of ABC transporter genes, down-regulation of the drug target and down-regulation of apoptotic genes. Several transcription factors such as RUNX2, SOX9, ETS1 and SMAD3 were up-regulated in the drug resistant cells. Targeted RUNX2 knockdown in the resistant cells using siRNA increased sensitivity to etoposide and also upregulated expression of pro-apoptotic genes indicating that RUNX2 could be a molecular target against etoposide resistance. Differential miRNA (microRNA) expression was observed among the drug resistant and sensitive cells suggesting that miRNA may also play a role in regulation of drug resistance. Hsa-miR-218, which targets ABCC6, was down-regulated in the drug resistant cell line. Transfection of a miR-218 mimic could down-regulate the expression of the efflux pump ABCC6 by 65% in drug resistant cells suggesting that regulation of miRNA may play an important role in etoposide resistance.
Project description:Gene expression profiling of immortalized human mesenchymal stem cells with hTERT/E6/E7 transfected MSCs. hTERT may change gene expression in MSCs. Goal was to determine the gene expressions of immortalized MSCs.
Project description:Kynureninase is a member of a large family of catalytically diverse but structurally homologous pyridoxal 5'-phosphate (PLP) dependent enzymes known as the aspartate aminotransferase superfamily or alpha-family. The Homo sapiens and other eukaryotic constitutive kynureninases preferentially catalyze the hydrolytic cleavage of 3-hydroxy-l-kynurenine to produce 3-hydroxyanthranilate and l-alanine, while l-kynurenine is the substrate of many prokaryotic inducible kynureninases. The human enzyme was cloned with an N-terminal hexahistidine tag, expressed, and purified from a bacterial expression system using Ni metal ion affinity chromatography. Kinetic characterization of the recombinant enzyme reveals classic Michaelis-Menten behavior, with a Km of 28.3 +/- 1.9 microM and a specific activity of 1.75 micromol min-1 mg-1 for 3-hydroxy-dl-kynurenine. Crystals of recombinant kynureninase that diffracted to 2.0 A were obtained, and the atomic structure of the PLP-bound holoenzyme was determined by molecular replacement using the Pseudomonas fluorescens kynureninase structure (PDB entry 1qz9) as the phasing model. A structural superposition with the P. fluorescens kynureninase revealed that these two structures resemble the "open" and "closed" conformations of aspartate aminotransferase. The comparison illustrates the dynamic nature of these proteins' small domains and reveals a role for Arg-434 similar to its role in other AAT alpha-family members. Docking of 3-hydroxy-l-kynurenine into the human kynureninase active site suggests that Asn-333 and His-102 are involved in substrate binding and molecular discrimination between inducible and constitutive kynureninase substrates.